CPU Frequency slightly below target

[spazbandicoot]

Hi there,

I have an i5-4690k installed in my computer and I've overclocked it to 4.2GHz in the BIOS (ASRock Z97 Anniversary).
The thing is, this frequency isn't actually reached; It only shows me a range of 4.1 - 4.15 GHz in Windows 10 Task Manager. I have looked in OpenHardwareMonitor and seen the same results.

I've seen people overclock thier CPUs and get successful results (Hitting the desired frequency, such as 5GHz in BIOS and 5GHz shown in Task Manager), but this just isn't the case with me.

I know 0.1 - 0.05GHz is not going to be much of a noticeable difference in performance but surely the clock speed should not change if CPU Fixed Mode is enabled in the BIOS, right?

Could this be something along the lines of too little voltage? If so/if not, please inform me.

Thanks

-Spaz

 

[Barty1884]

A lack of voltage isn't going to impact your clocks speeds - especially at idle. Even under load, too little voltage would just result in crashes, not an on the fly voltage drop.

Task Manager is not a reliable source, unfortunately.

What does CPU-Z show?

What, specifically did you change/set in the BIOS?

 

[spazbandicoot]

What I've changed in the BIOS from default settings:

There is a section for overclocking presets, I have selected the '4.2GHz boost' preset.
I have enabled a setting called 'Fixed mode'.
The OC preset just changes a few settings and the one thing that stands out to me is the voltage mode, it's set to 'Adaptive'. This voltage mode can be changed to 'Fixed'. Not to be confused with 'Fixed Mode'.

CPU-Z shows me a Core Speed of 4190MHz.

 

[Snipergod87]

Adjust your baseclock from Auto to 100.0 or even 100.1. These fluctuations are caused by fluxes in the baseclock, nothing to do with voltage.

 

[spazbandicoot]

Adjust your baseclock from Auto to 100.0 or even 100.1. These fluctuations are caused by fluxes in the baseclock, nothing to do with voltage.

I do not see a 'Baseclock' value to change anywhere in the BIOS of the ASRock Z97 Anniversary.

I changed a couple other things in the BIOS:

BLK Mode is set to High, as recommended in the BIOS for 'higher overclocking capabilities'.

CPU Voltage mode changed from 'Adaptive' to 'Override'. (This option was what I thought was named 'Fixed'.)

 

[Snipergod87]

It might be called core clock instead, but by default should be auto.
The base clock * multiplier = your clock speed
Often times the baseclock will drift from 100 to 99.9 or 99.8 or even more depending on how good the motherboard is.
For example a baseclock of 99.8 and a multiplier of 42 would result in a clock rate of 4,191.6Mhz.
I wouldn't bump up the base clock beyond 102-103Mhz as that can cause stability and data integrity issues on your PCI-Express bus, SATA bus, USB, basically every peripheral as it overclocks them all (Note this is not true for all Core series processors but it is the case in the 4th gen, some other series use a an external clock generator for the misc bus's)

 

[Barty1884]

Since you've selected a preset, there's probably a tweek to the BCLK in addition to the multiplier - as Sniper mentioned. Slight modifications (to 99.9 or 100.1 etc) aren't going to impact the other aspects of the board (PCIe slots etc), but will impact clock speeds.

42 @ 99 = 4158 which would be rounded to 4.15GHz.

Manually tuning your OC should allow >4.2GHz anyway, and avoid any confusion.


The presets can be used as a starting point, to get a feel for what the board/chip can do.... but typically they'll over-volt & can touch things that are unnecessary) like a BCLK.

 

[spazbandicoot]

there's probably a tweek to the BCLK in addition to the multiplier - as Sniper mentioned.

Ah yes, I've just found that. Changed value to 100.1 and the CPU now runs at 4202.03MHz according to CPU-Z.

Thanks everyone.

-Spaz